Scanning Electron Microscopy-energy Dispersive X-ray Spectroscopy Research Articles

Smart sustainable concrete: enhancing the strength and durability with nano silica

A detailed investigation was conducted to analyse the mechanical and durability features of a mixture of binary cement concrete modified with nanomaterials. In the context of the concrete matrix, the substitution of fractional cement content was carried out using Nano silica (NS) at concentrations of 1%, 2%, and 3%. Four distinct cementitious blends were subjected to a comprehensive match of tests, which encompassed compressive strength, flexural strength, split tensile strength, static modulus of elasticity, bulk density, water absorption, permeability, carbonation resistance, acid attack resistance, and rapid chloride penetration. The compositions of the mixes were investigated through the use of various microstructural analysis techniques, including scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (SEM-EDS), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). The research revealed significant improvements in the mechanical and durability characteristics of the material. An increment in the mechanical and durability properties of mixtures were seen due to inclusion of marble power and Nano silica due to enhanced pozzolanic activities of composite and its filling effect. It is worth mentioning that Nano silica has shown the potential to mitigate the degradation caused by exposure to sulfuric acid. The SEM-EDX analysis demonstrated a decrease in the Ca/Si ratio when compared to the reference combination, suggesting an increase in the consumption of calcium hydroxide (CH) and the creation of a more compact calcium-silicate-hydrate (C-S-H) gel. The X-ray diffraction (XRD) findings indicate that NS has the ability to act as an accelerator for pozzolanic processes. This is achieved by consuming calcium hydroxide (CH) and promoting the creation of extra calcium silicate hydrate (C-S-H), which ultimately enhances the overall performance of the concrete mixture.

Dissolution behavior and aging of iron–uranium oxide

Understanding the dissolution behavior of the fuel debris is necessary for the safe decommissioning of Fukushima Daiichi Nuclear Power Plants. The dissolution behavior of FeUO4 compounds formed by a high-temperature reaction of UO2 with iron, a stainless-steel component of reactor structural materials, was investigated under atmospheric conditions. The compounds were prepared in an electric furnace using U3O8 and Fe3O4 as starting materials, and their solid states were analyzed using X-ray diffraction, scanning electron microscopy–energy-dispersive X-ray spectroscopy, and X-ray absorption fine-structure spectroscopy. The fission products were produced via thermal-neutron irradiation. The concentration of nuclides dissolved in water was examined by performing static leaching tests of FeUO4 compounds for up to three months. A redox reaction was proposed to occur between trivalent Fe and pentavalent U ions in the early stage of FeUO4 dissolution. It was thermodynamically deduced that the reduced divalent Fe ion was finally oxidized into a trivalent ion in the presence of dissolved oxygen, and iron hydroxide limited the solubility of Fe. Meanwhile, the concentration of hexavalent U (i.e., uranyl ion) was limited owing to the presence of secondary minerals such as metaschoepite and sodium uranate and subsequently decreased, possibly owing to sorption on Fe oxides, for example. The concentrations of multivalent ions of fission products, such as Ru and Ce, also decreased, likely for the reason above. By contrast, the concentration of soluble Cs ions did not decrease. The validity of this interpretation was supported by comparing the results with the dissolution behavior of a reference sample (Fe-free U3O8).

Asbestos burden in lungs of non-occupationally exposed women from Broni (Pavia, Italy): a postmortem SEM-EDS study.

In Italy the incidence of malignant mesothelioma (MM) among women is remarkably high, due to the several contexts in which women had been exposed to asbestos. However, very few studies in literature focus on the inorganic lung content in women. The aim of this retrospective, observational study is to investigate the asbestos lung burden, in terms of concentration, dimensions and type of asbestos, in 42 women who died from MM and had been non-occupationally exposed to asbestos during the activity of the asbestos-cement plant located in Broni (Pavia, Northern Italy) where mainly chrysotile, crocidolite and amosite were used. Lung samples taken during forensic autopsies have been digested using sodium hypochlorite and filtered through a cellulose-ester membrane. The filter was examined using a scanning electron microscope and the chemical composition of the fibers was analyzed using an electron dispersive spectroscopy. The number of detected inorganic fibers, asbestos fibers and asbestos bodies (ABs) were normalized to 1 gram of dry tissue. In six samples no asbestos has been detected. Overall, the most represented kind of asbestos was amosite, followed by crocidolite, tremolite/actinolite asbestos and chrysotile. The concentration of all inorganic fibers was significantly higher in women with environmental and household exposures compared with those with only environmental exposure (P=0.025), as well as the concentration of asbestos fibers (P=0.019) and ABs (P=0.049). We found a significant correlation between the concentration of asbestos fibers and the duration of exposure (rho =0.413, P=0.008), as well as with the latency of MM (rho =0.427, P=0.005). The distance of the residential address from the factory and the time spent daily in contact with asbestos did not influence the lung asbestos burden. These results suggest the relevance of the lung clearance of asbestos, regarding mainly chrysotile. As a consequence, although scanning electron microscopy -energy dispersive X-ray spectroscopy (SEM-EDS) is considered the most reliable tool for assessing previous exposure to asbestos, its results should be interpreted with caution, especially in a legal context. In addition, our data confirm the relevance of environmental and household exposure in determining asbestos concentration in lungs and highlight the importance of household exposure.

WHOLE ROCK AND CLAY MINERALOGY OF EARLY MIOCENE SEDIMENTARY ROCKS OUTCROPPING IN THE NORTHEAST OF KORKUT (MUŞ-TÜRKİYE)

This study was carried out to reveal the origins and formations of the minerals by determining the mineralogical compositions of Early Miocene aged sedimentary rocks outcropping in the northeast of Korkut district, 20 km from Muş. 75 rock samples were taken by measuring two stratigraphic sections from Mollababa Formation (Aquitanian) and Aktaş Formation (Burdigalian) cropping out in the study area. XRD (X-ray diffraction) WR (whole-rock) analyzes were performed on these rock samples, and calcite, quartz, feldspar, clinoptilolite and clay minerals were determined in their compositions. CF (clay fraction) mineralogical compositions were determined by performing XRD detailed clay analyzes on 20 selected rock samples. In clay fractions; chlorite, illite, serpentine, mixed- layered chlorite-vermiculite (C-V) and non-clay minerals such as calcite, quartz and feldspar were determined. SEM-EDS (scanning electron microscope - energy dispersive X-Ray Spectroscopy) studies were carried out on five selected samples, and in addition to clay minerals such as feldspar, calcite, chlorite and C-V, fossils were also observed. When all the data were evaluated, it was interpreted that the chemical and biogenic origin of the calcite mineral, the detrital origin of the quartz, feldspar, chlorite and serpentine minerals, the neoformation product of clinoptilolite, C-V mineral formed from dark-colored minerals with negative transformation.

The novel ternary phase CaAl2±xCr2±xO7 in the Al2O3–CaO–Cr2O3 system: What is the chromium solubility?

Recently, in the Al2O3–CaO–Cr2O3 system, a Cr3+ ternary phase named wuboraite (CaAl2Cr2O7) was synthesized for the first time in an air atmosphere, which later showed an undetermined hint of solid solubility between Cr3+ and Al3+ in different atmosphere. In the present investigation, the solubility limits (or x values) of the CaAl2±xCr2±xO7 were determined by conducting high-temperature equilibrium experiments in both air and N2 atmospheres with the various proportionate mixtures of CaO, Al2O3, and Cr2O3, and subsequently using powder X-ray diffraction (XRD) and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) analysis. In the air atmosphere, the Cr richest end-member of the Wuboraite solid solution phase is CaAl1.77Cr2.23O7 (or x = 0.23), while that of Al richest end-member is CaAl2.18Cr1.82O7 (or x = 0.18). Whereas, in the N2 atmosphere, the Cr richest end-member of the wuboraite solid solution phase is CaAl1.77Cr2.23O7 (or x = 0.23), while that of Al richest end-member is CaAl2.15Cr1.85O7 (or x = 0.15).

Samarium-modified NBT ceramics: a comprehensive exploration of cumulative effects

In the present report, ceramic specimens of sodium bismuth titanate [Na0.5(Bi1-xSmx)0.5TiO3] were prepared through solid-state reaction method with variations in the dopant concentrations specifically, x = 0.0, 0.1, 0.3, 0.5. The structural, optical, mechanical, and magnetic properties of lead-free NBT ceramics were investigated. The rhombohedral phase with space group R3c was confirmed in all prepared ceramic samples using X-ray diffraction patterns and Rietveld analysis. SEM micrographs and Energy Dispersive x-ray spectroscopy (EDAX) assess the morphology, grain size, overall structure, and stoichiometry of the developed compounds. FTIR spectroscopy was used for characterizing and identifying the functional groups. UV–vis spectroscopy revealed that band gap values decreased as dopant concentration increased, confirming the use of NBT-based perovskite as a photoactive material. PL spectra at room temperature exhibited reddish-orange emission. Colour coordinates and CCT values are in the range of 3483 K to 5912 K. At a concentration of x = 0.3, the materials displayed a high Vickers hardness of 8.20 GPa and exhibited minimal wear with low frictional coefficient values. Ferromagnetic behaviour at room temperature (RTFM) was detected in Sm-modified ceramic samples, as confirmed by the VSM study. The cumulative effect impact of the rare earth dopant cation at the Bi-site of NBT was widespread and demonstrated significant potential for use in optoelectronic devices.

Gravity driven ceramic membrane loaded birnessite functional layer for manganese removal from groundwater: The significance of disinfection on biofilm

Gravity-Driven Ceramic Membrane (GDCM) technology has gained popularity and recognition in water purification on account of its low energy consumption and convenient operation. This study aimed to comprehensively assess the effects of different disinfectants, including hydrogen peroxide (H2O2) and sodium hypochlorite (NaClO), on GDCM performance. It focused on the change in manganese removal and structure of the powdered activated carbon (PAC) - manganese oxides (MnOx) pre-deposited at the membrane interface and as well membrane fouling mitigation. The results showed that after the first two disinfection cycles, the flux recovery was 15 LMH for H2O2, while using NaClO only achieved an average recovery of 2 LMH and increased the effluent manganese, exceeding 0.1 mg/L within a short period of time. During the disinfection process, H2O2 exhibited better performance in mitigating membrane fouling compared to NaClO in the GDCM system. Additionally, by observing the recovery time of Mn2+ after disinfection, it can be deduced that the initial manganese removal mainly resulted from biological action of manganese-oxidizing bacteria (MnOB), while the later stage relied primarily on the catalytic oxidation action of birnessite. Fluorescence excitation–emission matrix analysis (EEM) indicated that most organic compounds dissolved in the disinfectant solution after disinfection, with some permeating through the membrane, while the remaining portion continued to accumulate in the filter cake layer. This accumulation was further confirmed by the enhanced absorbance peaks of functional groups (–NH and –OH) in the Fourier-transform infrared spectroscopy (FTIR). Scanning electron microscope - energy dispersive x-ray spectroscopy (SEM-EDS) mapping analysis revealed that MnOx formed more lamellar structures between nano-flower balls after disinfection. This increased the number of active sites and opened up water flow channels, contributing to improved flux. X-ray photoelectron spectroscopy (XPS) analysis demonstrated that Mn3+ as the dominant valence in MnOx exhibited excellent catalytic oxidation ability. Raman analysis and X-ray diffraction (XRD) indicated that MnOx showed consistent Raman spectra with birnessite before and after disinfection, and the oxidative effect of disinfection did not alter the crystal structure of MnOx. This result demonstrates the importance of applying effective disinfection in the GDCMs.

Characterization of a Moderately Halotolerant Antimony-Removing Desulfovibrio sp. Strain Isolated from Landfill Leachate

Antimony (Sb) is a harmful contaminant posing a risk to the environment and human health. Antimony-containing industrial wastewater often contains sulfate; therefore, it is suitable to apply sulfate-reducing bacteria (SRB) to remove Sb from such water. SRB anaerobically reduce sulfate to sulfide. Sb(V) is then reduced to Sb(III) by sulfide to produce an antimony trisulfide (Sb2S3) precipitate. This wastewater often exhibits a high salinity, which inhibits biological reactions. This study aimed to isolate and characterize a halotolerant bacterium capable of removing Sb from wastewater. A Desulfovibrio sp. strain was isolated from a mixed bacterial culture derived from a leachate sample from the Nam Son landfill in Vietnam. The isolated strain, NSLLH1b, removed 86% of the 50 mg/L of Sb(V) in 3 days at 180 mg/L of sulfate and 360 mg-C/L of lactate, at a pH of 7.0 and at 28 °C. It anaerobically removed >80% of the Sb(V) at 12.5–100 mg/L in 14 days at initial concentrations of >100 mg/L of sulfate, >250 mg-CL of lactate, and 0.2–15 g/L of NaCl, and a pH of 5–8, resulting in orange precipitation. An analysis using scanning electron microscopy–energy-dispersive X-ray spectroscopy confirmed that the precipitation consisted mainly of Sb and sulfur, supposedly as Sb2S3. This moderately halotolerant bacterium can be used for simultaneously removing Sb and sulfate from wastewater.

Carbonated Hydroxyapatite Extracted from Indonesian’s Eggshell Biogenic Wastes as Bioceramic Materials

Carbonated hydroxyapatite (CHA), with a chemical composition close to the mineral found in human bone, represented higher solubility than stoichiometric hydroxyapatite (HA). Therefore, the B-type CHA is commonly used for bone tissue engineering. This study fabricated B-type CHA using Indonesian eggshells from chicken, organic chicken, and duck because of the high calcium carbonate (CaCO3) content (94%). A co-precipitation method was used for synthesizing CHA. The physicochemical properties of the CHA were characterized using Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDS), X-Ray Diffractometer (XRD), and Fourier Transform Infrared Spectroscopy (FTIR). Based on FTIR results for CHA, the stretching functional groups of B-type CO3 were detected at 1452-1453 cm-1, 1417-1418 cm-1, and 873-874 cm-1, which indicated the formation of B-type CHA. Meanwhile, CHA from organic chicken eggshells had low crystalline properties and the best morphology due to a more homogeneous and uniform agglomeration. More specifically, CHA based on organic chicken eggshells has a Ca/P molar ratio following natural human bone, which is 1.71. Therefore, all B-type CHA samples are candidates in bioceramic materials for bone tissue engineering applications.

Green synthesised nanocopper/chitosan aerogel biocomposite as a recyclable and nonprecious catalyst for methyl orange reduction

Methyl orange (MO), which is known as a highly durable dye that is extremely toxic to humans and animals, has been processed by using various methods. In recent years, MO degradation through reduction in the presence of NaBH4 (NB) and suitable nanocatalyst have garnered considerable interest. However, the nanosized particles of the catalyst make separation from the liquid solution more difficult and limit the practical application of this technique. Herein, copper nanoparticles (CuNPs) decorated on three-dimensional chitosan aerogel (CSA) were synthesized as a reusable composite for the catalytic degradation of MO by using a green method with durian (Durio zibethinus) shell (DS) extract as a reducing agent. The Cu/CSA composite’s physicochemical properties were characterized by using X-ray Diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Scanning electron microscopy- energy dispersive X-ray spectroscopy (SEM-EDS), high resolution Transmission electron microscopy (HR-TEM), Brunauer-Emmett-Teller (BET) and Raman spectroscopy. These modern techniques elucidated the structure and formation of copper nanoparticles on the CSA surface. The copper nanocatalysts have an average particle size of 32.6 nm, specific surface area of 55.8 m2/g, pore size of 32 Å and pore area of 0.049 cm3/g. Through the investigation of catalyst activity, the conditions of MO reduction were optimised with the 1.0 Cu/CSA sample, catalyst dose of 0.5 g/L and a molar ratio of MO/NB of 1/200. The reaction reached over 94.3% efficiency after 10 min, correlating with a kinetic rate constant of 0.163 min−1. It is worth mentioning that the optimized catalyst can be conveniently synthesized and retrieved from the reaction solution in just 5 s using a vacuum filter. Furthermore, its effectiveness remains largely unaffected even after undergoing five cycles of reuse, thus demonstrating its exceptional durability and potential in environmental remediation.

Sustainable gliadin - Metal oxide composites for efficient inactivation of Escherichia coli and remediation of cobalt (II) from water

Bio-based materials facilitate greener approach to engineering novel materials with multifunctional properties for various applications including water treatment. In this study, we extracted gliadin from wheat gluten using alcoholic solvent. The aggregation limitations of gliadin protein were overcome by functionalisation with metal oxides (MOs) TiO2, AgFe2O3 and AgFe–TiO2 prepared by chemical precipitations. The novel composites were characterised by scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), Fourier-transform infrared spectroscopy (FTIR), X-Ray diffraction (XRD), thermogravimetry analysis (TGA), Brunauer Emmet–Teller (BET), and zeta potential. The multifunctionality of MOs-gliadin composites was tested through toxic Escherichia coli (E. coli) inactivation and Co2+ adsorption from water. The antibacterial results showed excellent inhibition under both dark and light conditions. The maximum Co2+ uptake, 101 mg/g was reached with TiO2@gliadin after 24 h and best fitted the Langmuir isotherm model. The adsorption process followed pseudo-second order model with an equilibrium adsorption capacity, qe2= 89.86 mg/g closer to the experimental data. Thermodynamic investigations indicated that ΔG°=−9.677kJ/mol,ΔH°=−123kJ/mol,and ΔS°=0.490J.K/mol, respectively, suggesting that adsorption was spontaneous and endothermic. The regenerated TiO2@gliadin composite was still efficient after five consecutive cycles. This study demonstrates that MOs-gliadin blended composites are sustainable for water purification.

Preparation of foam concrete from solid wastes: Physical properties and foam stability

The method for preparation of foam concrete from solid wastes were proposed in this study, where soda residue (SR), calcium carbide slag (CS), grand granulated blast-furnace slag (GGBS) and fly ash (FA) were used as raw materials for the binder and Al powder was used as the foam agent. The effects of Al powder, stabilisers and FA content on the dry density as well as compressive strength were assessed to determine the optimal mix proportions. Moreover, to understand the foaming process, the influence of stabilisers on the zeta potential and surface tension of the fresh mixes were measured and Low-Field Nuclear Magnetic Resonance (LF-NMR) was employed to qualitatively characterize the pore size distribution. Finally, the hydration products were analyzed by X-Ray Diffraction (XRD), Fourier transform infrared spectrometer (FTIR), Thermogravimetric Analysis-Differential scanning calorimetry (TGA-DSC), Scanning electron microscope-Energy dispersive X-ray spectroscopy (SEM-EDS). The results suggested that the optimal content of Al powder was 1–2%, and the combination of S and P (SP) stabilisers showed better stabilization effect than the single use of S or P, leading to well distributed foam with smaller size. The stabilization effect was attributed to the dissolved negative complex that absorbed on the foam film to increase the repulsion between foams as well as to reduce the surface tension of the fresh mixture. The substitution of GGBS by FA generally resulted in reduced dry density and compressive strength, while the extent varied with the addition of stabilizers, and thus the optimal amount of FA depended on the selection of stabilisers. Overall, our study highlighted the potential of using industrial waste materials for producing sustainable light weight concrete with satisfactory dry density and compressive strength.

Molecular dynamics simulation and experimental research on the influence of SiO2-H2O nanofluids on wettability of low-rank coal

Coal dust pollution is one of the problems needing urgent solution in global coal mining industry. Exploring environmental and efficient new wetting agents of coal dust has potential application value in the field. Taking the Wender model as the research object, Materials Studio molecular simulation software was used and physical experiments were conducted to study the influence mechanism of SiO2-H2O nanofluids on the wettability of low-rank coal (LRC). Results show that SiO2 nanoparticles (NPs) have a relatively high surface electrostatic potential, enabling strong binding capacity with LRC and water molecules. After SiO2 NPs are adsorbed on the LRC surface, more water molecules are adsorbed on the surface, which enlarges the interaction energy between solid-liquid molecules in the system. As the number of SiO2 NPs increases, the thickness of SiO2 NPs, thickness of coal-water interface, and mean square displacement (MSD) of water molecules all enlarge and the wettability of coal dust is enhanced. Compared with water, SiO2-H2O nanofluids have a lower surface tension and a smaller contact angle. The scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) results further verify that the adsorption and aggregation of SiO2 NPs on the surface of coal dust are the essential cause for the enhanced wettability of coal dust. The molecular dynamics simulation results and experimental results are mutually verifiable, laying a theoretical basis for enhancing the wettability of coal dust using SiO2-H2O nanofluids.

The Isolation and Characterization of Cellulose Nano crystals from Baobab Pod Fibres using Acid Hydrolysis

In this research, cellulose nanocrystals were isolated from locally grown baobab pod fibres. Fibres were treated chemically using NaOH and then hydrolysed using Nitric acid. The effect of NaOH treatment and acid hydrolysis on surface morphology, crystallinity, and thermal properties of fibres were investigated using Fourier Transform Infrared (FTIR), Scanning electron microscopy/Energy dispersive X-ray spectroscopy (SEM/EDS), X-ray Diffraction(XRD) and Thermogravimetric analysis (TGA/DTA). From the results evaluated, cellulose content of 17.9 % was recorded after NaOH treatment and 25.3 % was recorded after acid hydrolysis, the crystallite size was found to be 3.003 nm and thermal stability of the fibre was enhanced after chemical treatment and acid hydrolysis. Based on the results obtained, it shows that nanocellulose hydrolyzed from baobab pod fibres has excellent properties for use as polymer reinforcement and for other engineering applications.

An efficient catalytic reduction of nitroarenes over metal‐organic framework‐derived magnetic graphitic carbon nitride nanosheet

Metal–organic frameworks (MOFs) have emerged as highly viable and environmentally friendly alternatives to traditional catalysts within the catalytic family. This project delves into the investigation and subsequent reporting of the remarkable catalytic performance exhibited by magnetic Ox‐CN‐Cu‐MOF in the reduction of nitroarenes. The synthesis of magnetic Ox‐CN‐Cu‐MOF was achieved through a streamlined and intricate process, with its structure meticulously identified via various analytical methods including high‐resolution transmision electron microscopy (HRTEM), X‐ray diffraction (XRD), scanning electron microscopy/energy dispersive X‐ray spectroscopy (SEM/EDS), Fourier transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET), vibrating‐sample magnetometry (VSM) and thermogravimetric (TG) analysis. Of particular significance, the loading of copper (Cu) and its potential leaching were effectively detected through inductively coupled plasma optical emission spectroscopy (ICP‐OES) analysis. The catalytic efficacy of magnetic Ox‐CN‐Cu‐MOF was evaluated during the conversion of nitro compounds o related‐amines utilizing NaBH4 as the reductant. Remarkably, the unique structure and Lewis acidic properties of copper in the metal nodes contributed to the exceptional catalytic behavior exhibited by the magnetic Ox‐CN‐Cu‐MOF catalyst, surpassing that of previously reported catalysts. Furthermore, magnetic Ox‐CN‐Cu‐MOF demonstrated exceptional recyclability, as validated through repetitive continuous usage.

WO3 dispersed on a titanium porous clay heterostructure as a highly efficient visible light-active photocatalyst

Nanocomposites of WO3-dispersed titanium-porous clay heterostructures (W/Ti-PCH) from montmorillonite raw clay were synthesized and reported for the first time in this paper. The nanocomposite was prepared by impregnating tungstophosphoric acid into the titanium-porous clay heterostructure (Ti-PCH). The physicochemical features of the nanocomposite were characterized by using X-ray diffraction (XRD), scanning electron microscopy energy dispersive X-ray spectroscopy (SEM-EDS), high-resolution transmission electron microscopy (HRTEM), UV–visible diffuse reflectance UV–visible spectroscopy (UV-DRS), X-ray photoelectron spectroscopy (XPS) and gas sorption analyses. Identification using XRD and XPS revealed that the dispersion of WO3 anchored on the Ti-PCH surface led to an increase in the band gap energy of the material from 3.1 eV in Ti-PCH to 3.22 eV in W/Ti-PCH. The improved characteristics support the excellent photocatalytic activity for RhB degradation, as 99.99 % removal was achieved after 15 min of treatment.

Rare Earth Element Characterization of Bledug Kuwu Mud Volcano, Central Java, Indonesia, based on Geochemical Analyzes (Susceptibility, XRF, XRD, SEM-EDS and ICP-EOS)

Mud volcano material is generally rich in oxides, while oxides are the main compounds forming rare earth elements. Bledug Kuwu, Central Java, Indonesia, is one of the active mud volcanoes, so there may be rare earth elements. This research is the characterization of rare earth elements (REE) in the Bledug Kuwu mud using magnetic and geochemical methods. Magnetic characterization uses magnetic susceptibility measurements. The geochemical characterization of the mud samples consisted of the XRF (X-Ray Fluorescence), XRD (X-Ray Diffraction), ICP-EOS (inductively coupled plasma) test, and the SEM-EDS (Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy) test. The results of the geochemical analysis of the Bledug Kuwu mud sample were the content of quartz, kaolinite, and calcite with an average concentration of 42.26%, 23.67%, and 33.96%. The susceptibility of Kuwu's mud is 0 because the concentration of metal elements is low; according to the results of XRF, XRD, and SEM tests identified the main mud elements as C, O, Si, Ca, and Al. The rare earth elements in Kuwu's mud are Ce, Dy, Eu, Gd, Ho, La, Nd, Pr, Sm, Tb, Y, and Sc. The highest concentrations were Ce 52.22 ppm and La 47.95 ppm.

Effect of a harsh circular environment on self-healing microbial-induced calcium carbonate materials for preventing Pb2+ migration

Microbially induced carbonate precipitation (MICP) is increasingly being explored for Pb-contaminated water bodies and soil remediation. However, the Pb-related precipitate resulting from the MICP process can possibly leach acid over time when subjected to harsh environments, causing serious threats to human health. In this study, for the first time, self-healing microbial-induced calcium carbonate (MICC) materials are proposed and applied to prevent Pb2+ migration where the Pb-related precipitate is acid leached after spore germination, spore-vegetative cell transformation, urease secretion, and urea hydrolysis, thereby producing spore-containing precipitation. This process was repeated five times to explore the effect of a harsh circular environment on self-healing MICC materials. Results indicated that Pb immobilization would have deteriorated if the inosine and trace elements had not been intervened during spore germination and spore-vegetative cell transformation, respectively. The spores and vegetative cells provided extra nucleation sites for Pb2+ and minerals to attach. The extracellular polymeric substances (EPSs) combined Pb2+ with functional groups and chemical bonds to prevent their migration to surrounding environments. The scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM–EDS) images also indicated that the cerussite mineral was precipitated prior to the calcite mineral because Pb2+ had more affinity to combine with CO32- and OH-. An immobilization efficiency of greater than 95% remained nearly the same after five cycles, while it reduced very quickly to less than 10% after three cycles when neglecting the self-healing MICC materials, thus highlighting their relative merits.

Synthesis and characterization of eco-friendly TiO2 nanoparticle from combine extract of onion and garlic peel

Plant extracts are increasingly being used to make green nanoparticles since they are harmless and environmentally friendly. The process provides a cheap technique to create nanoparticles. TiO2 nanoparticles were created in this work using titanium isopropoxide and a combination of onion and garlic peel extracts. X-ray diffraction (XRD), scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS), ultraviolet–visible spectroscopy (UV–Vis), and Fourier transform infrared (FTIR) spectroscopy were used to analyze the green-generated TiO2 nanoparticles containing the extract. The sharp and potent peaks at 2 values of 27.45°, 37.97°, 44.07°, 54.40°, and 69.85° have been used to confirm the configuration of the crystalline nanoparticles (NPs) of TiO2. With the exception of the inescapable adsorption of moisture on the surface in the open air, calcined TiO2 NPs exhibit FT-IR absorption bands that show the purity of the produced nanoparticles. The bactericidal activity of green TiO2 NPs and unprocessed extracts of onion and garlic peels were examined using the disc diffusion method. In comparison to a crude mixed extract, NP is more efficient against Gram-positive and Gram-negative bacteria because to its smaller average crystalline size and consistent shape, which are visible in SEM pictures.

The Influence of Alumina Airborne-Particle Abrasion on the Properties of Zirconia-Based Dental Ceramics (3Y-TZP)

The objective of this study was to assess the effect of airborne-particle abrasion with alumina particles of various sizes (50 μm, 110 μm, 250 μm) on the surface properties of 3Y-TZP (3 mol% yttria-stabilized tetragonal zirconia polycrystals). The analysis comprised the Vickers hardness test (HV1kp), a surface roughness evaluation (Ra, Rq, Rz, Rsk, Rsm, Rt, Vo, profile displays), and SEM–EDS microanalysis (scanning electron microscopy–energy-dispersive X-ray spectroscopy). Any statistical relationships were assessed using the Kruskal–Wallis one-way analysis-of-variance-by-rank test (p = 0.05). While airborne-particle abrasion with 50 µm alumina significantly increases the Vickers hardness of 3Y-TZP (1678.8 HV1kp), 110 μm and 250 μm alumina particles do not appear to have any such effect. The surface roughness of 3Y-TZP increases with the size of the alumina particles (Ra, Rq, Rz, Rt, Vo: vertical plane and retention volume assessment); a higher Rsm (horizontal plane assessment) was noted for specimens air-abraded with 250 µm alumina particles; air abrasion with 50 μm alumina particles yielded a symmetrical surface roughness profile (Rsk). The major topographic pattern of the surface of 3Y-TZP is altered by alumina airborne-particle abrasion, with larger alumina particles causing more severe changes. Aluminum traces on the 3Y-TZP surface are observed. The shape of the alumina particles is irregular, with rough edges; the size of the alumina particles plays a significant role in the air abrasion of zirconia-based dental ceramics, affecting their morphology and properties.